1. Field of the Invention
This invention relates to a method of blocking free radical processes in an animal which result in mediated pathology without accompanying deleterious pro-oxidant side reactions, and, more particularly, to administration of an extract of the fruit of the Emblica officinalis plant to effect such result.
2. Description of the Prior Art
The biomedical literature has recognized that xe2x80x9cfree radicalsxe2x80x9d and other reactive species are involved in different human diseases. These species have been implicated in over 100 disorders, ranging from rheumatoid arthritis and haemorragic shock to cardiomyopathy and cystic fibrosis to gastrointestinal ischaemia, AIDS and even male pattern baldness. Some of the clinical conditions in which the involvement of free radicals is given in Table 1 below.
These pathologies have been alleviated with antioxidants which function as blockers of such radical process. However, an antioxidant cannot distinguish between radicals that play a useful physiologic role and those that are harmful. Moreover, antioxidant compounds not only function as antioxidants, but they may have pro-oxidant action as well. Examples of antioxidants which also exhibit pro-oxidant activity are given below:
Vitamin C
Vitamin C is a hydrophilic vitamin with well-known antioxidant properties; however Vitamin C also can act as a pro-oxidant in the following manner. Specifically, the combination of Vitamin C with Fe3xe2x88x92 or Fe2+ ions causes intense oxidation of polyunsaturated fatty acids (PUFAs). The mechanism of such pro-oxidation is as follows:
The Vitamin C radical (dehydroascorbate radical anion, Vit C.), a relatively non-reactive species, can decay by disproportionation resulting in the production of Vitamin C and dehydroascorbate (DHA), thereby terminating the propagation of free radical reactions:
xe2x80x832Vit C.+2H+xe2x86x92Vit C+DHA
Alternately, the vitamin C radical may reduce another Fe""+ ion:
Vit C.+Fe3+xe2x86x92DHA+Fe2+
During oxidation of Vitamin C, H2O2 is also formed:
Vit C+O2xe2x86x92DHA+H2O2 
The reduction of Fe3+ thus appears to be the probable cause for the pro-oxidant action of Vitamin C. The degree of ferric ion reduction may therefore determine the prevalence of Vitamin C acting either as an antioxidant or as a pro-oxidant.
Vitamin E
The propagation reaction of the oxidative breakdown of PUFAs, indicated as LH, is shown below, where K1 is the equilibrium constant: 
In which LOO. indicates lipid peroxyl radicals.
The lipid-soluble Vitamin E thus owes its antioxidant activity to trapping of LOO., which in turn is reduced to stable LOOH (lipid hydroperoxides), as follows: 
Vitamin E itself is a mixture of four lipid-soluble tocopherols (designated as xcex1, xcex2, xcex3 and xcex4); xcex1-tocopherol being the most active with respect to trapping of peroxyl radicals. The resonance stabilization of Vit E derived from xcex1-tocopherol renders it less reactive than LOO., therefore, Vitamin E is a good antioxidant.
In contrast, Vitamin E, if present at a relatively high concentration, can induce deleterious radical formation by a side reaction with LOOH, thus functioning also as a pro-oxidant.
Vit E+LOOHxe2x86x92Vit E.+LO.+H2O
Superoxide Dismutase (SOD)
Intra-articular administration of Cu/Zn-containing SOD has been used to prevent free radical damage. However, H2O2, a reaction product of O2xe2x88x92 dismutation, can inactivate SOD. Therefore, in the presence of H2O2, SOD will act as a pro-oxidant.
Glutathione (GSH)
Thiol (SH) groups are essential in the protection against the deleterious effects of reactive oxygen species. The tripeptide GSH (xcex3-Glu-Cys-GLY) is the pivot in various protective systems. In addition, the SH group is important for the function of many proteins. To protect the SH groups of proteins, high concentrations of the reducing GSH are required. However, it is difficult to estimate the level of GSH needed for this function since thiols may exhibit both antioxidant and pro-oxidant actions. The pro-oxidant activity of the thiol GSH can be simply explained as involving the reduction of Fe2+. Hence, a generally accepted antioxidant, such as GSH, may possess deleterious pro-oxidant activity under certain conditions.
Accordingly, it is an object of this invention to provide a method of blocking free radical processes which result in mediated pathology without deleterious pro-oxidant side reactions.
Another object of the present invention is to provide advantageous antioxidant activity to block free radical processes without accompanying pro-oxidant side reactions by administration of an extract of the fruit of the Emblica officinalis plant, optionally including one or more additional antioxidants.
A feature of the invention is the provision of a use formulation containing an active use level of said extract in the amount of about 0.005 to 5% by weight of said formulation.
These and other objects and features of the invention will be made apparent from the following description thereof.
What is described herein is a method of blocking free radical processes in an animal which result in mediated pathology without deleterious pro-oxidant side reactions. The method comprises administering an extract of the fruit of the Emblica officinalis plant to effect such advantageous result. In practice, a use formulation containing an active use level of said extract in an amount of about 0.005 to 5% by weight of the formulation, is utilized for such administration. Optionally one or more additional antioxidants may be included in the formulation.